[PATCH] sata_sil24: update sil24_hardreset()

Use phy debouncing instead of unconditional wait after DEV_RST and
make sil24_hardreset() to request followup SRST as that's the only way
to wait for !BSY.  Note that the original implementation never worked
- if the cached status was !BSY, ata_busy_sleep() finished
immediately; otherwise, it timed out regardless of the actual device
status.

Signed-off-by: Tejun Heo <htejun@gmail.com>

diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index a39e8d0..4a83090 100644 (file)
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -591,7 +591,7 @@ static int sil24_hardreset(struct ata_port *ap, unsigned int *class)
 {
        void __iomem *port = (void __iomem *)ap->ioaddr.cmd_addr;
        const char *reason;
-       int tout_msec;
+       int tout_msec, rc;
        u32 tmp;
 
        /* sil24 does the right thing(tm) without any protection */
@@ -605,10 +605,14 @@ static int sil24_hardreset(struct ata_port *ap, unsigned int *class)
        tmp = ata_wait_register(port + PORT_CTRL_STAT,
                                PORT_CS_DEV_RST, PORT_CS_DEV_RST, 10, tout_msec);
 
-       /* SStatus oscillates between zero and valid status for short
-        * duration after DEV_RST, give it time to settle.
+       /* SStatus oscillates between zero and valid status after
+        * DEV_RST, debounce it.
         */
-       msleep(100);
+       rc = sata_phy_debounce(ap, sata_deb_timing_before_fsrst);
+       if (rc) {
+               reason = "PHY debouncing failed";
+               goto err;
+       }
 
        if (tmp & PORT_CS_DEV_RST) {
                if (ata_port_offline(ap))
@@ -617,15 +621,13 @@ static int sil24_hardreset(struct ata_port *ap, unsigned int *class)
                goto err;
        }
 
-       if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
-               reason = "device not ready";
-               goto err;
-       }
-
-       /* sil24 doesn't report device class code after hardreset,
-        * leave *class alone.
+       /* Sil24 doesn't store signature FIS after hardreset, so we
+        * can't wait for BSY to clear.  Some devices take a long time
+        * to get ready and those devices will choke if we don't wait
+        * for BSY clearance here.  Tell libata to perform follow-up
+        * softreset.
         */
-       return 0;
+       return -EAGAIN;
 
  err:
        ata_port_printk(ap, KERN_ERR, "hardreset failed (%s)\n", reason);